Means for shield tunnelling



Aug. 1947- A. D. G. WILSON V MEANS FOR SHIELD TUNNELLING Filed Feb. 6,1945 FIG].

Inventor Batented Aug. 5, 1947 MEANS FOR SHIELD TUNNELLING Alford DonaldGratton Wilson, Buckhurst Hill, England Application February 6, 1945,Serial No. 576,491 In Great Britain February 3, 1944 3 Claims.

This invention relates to a means for shield tunnelling.

In known methods of tunnelling it is common to use a shield of themechanical excavator or other type to effect or assist the excavationand thereafter to support the ground whilst the lining is being erectedwithin the tail of the said shield.

The object of the present invention is to speed up and cheapen tunneldriving by an improved method which consists in employing a combinationof two shields, or an excavating device and a trailing sheld so thatexcavating may proceed simultaneously with the erection of the lining inthe trailng shield.

In the accompanying drawing which diagrammatically illustrates anembodiment of this invention:

Figure 1 is a longitudinal section, on line I-I of Figure 2, and,

Figure 2 is a transverse section (the right-half being a section on lineII'II, the left-half being a section on line III-III) of Figure 1.

According to this invention, which will be described with reference tothe use of a leading or digger shield I, and a trailing or main shield2, the leading shield I which may be of any ordinary construction exceptthat it is unprovided with the usual tail, and having at its front end arotary cutter 3, is furnished around the circumference of its rear facewith a plurality of hydraulic rams 4, the rear or outer ends 5 of whichare adapted to bear against thrust blocks or a thrust plate 6 providedon the front face of the trailing shield 2.

The trailing shield 2, is of larger diameter than the leading shield I,but is otherwise of similar construction thereto being provided with aplurality of rams I the rear or outer ends of which are furnished withshoes 8 adapted to bear against a part of the lining erected behind thetrailing edge of the shield, such for example as the joist 9.

In operation, when the leading shield I has reached the end of its runand the rams 4 are fully extended as shown in Figure 1, the rams 4 arethen retracted, after which the rams I of the trailing shield 2 areextended thereby forcing said shield forwardly the cutting edge Inthereof trim- 2 ming the cut made by the leading shield I. The lining ofthe tunnel thus formed may be effected in any known manner to the rearof the trailing shield as the latter is moved forward.

What I claim is:

1. Tunnelling device comprising a leading shield of substantiallycylindrical form carrying on its front cutting means, a plurality ofrear- Wardly directed hydraulic rams arranged along the periphery ofsaid leading shield near the rear edge thereof, a substantiallycylindrical trailing shield provided adjacent its front edge withabuttments forming bearings for the free rear ends of said rams, thelatter in their fully collapsed positions having a length to prevent thefront edge of the trailing shield from reaching the rear edge of theleading shield so that the two shields are independent of one anotherexcept that the trailing shield provides the reaction for the forwardmovement of the leading shield.

2. Tunnelling device, as claimed in claim 1, in which the trailingshield has a diameter exceeding that of the leading shield so that itsfront edge operates to trim the cut made by the leading shield.

3. Tunnelling device, as claimed in claim 1, including shoes on the freerear ends of said hydraulic rams, said trailing shield being provided ata short distance behind its front edge with an inwardly projectingannular flange against which said shoes bear.

ALFORD DONALD GRATTON WILSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 675,355 MacHarg May 28, 1901FOREIGN PATENTS Number Country Date 20,322 Great Britain 1906 64,335Germany 1892 67,098 Germany s 1893 105,768 Germany 1899

